Blast gun



L. LANZA BLAST GUN Feb; 4, 1941.

Filed Deo. 25, v1939 Patented Feb. 4, 1941 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to devices for admixing particles of matter with a stream of iiuid and has particular reference to such a device useful in sand blasting.

It is an object of the inventionV to provide a multi-purpose tool particularly designed for use in small industrial shops, which will perform, when connected with a source of compressed air, numerous blowing or suction operations that heretofore required the use of a large assortment of separate tools each designed for a specific purpose.

Another object of the invention is to provide a gun for admixing with a stream of air materials, such as sand, which is materially simplified in construction over those now on the market thereby making its production cost very low and permitting it to be sold at a price which is well within the reach of smaller industrial shops or homeowners.

A further object of the invention is to provide, in a device for admixing air and materials such as sand and for conducting the admixed materials through a discharge duct, means in the discharge duct for introducing, into the admixture, additional quantities of air.

A still further object of the invention is to provide a blast gun for the use described which may be very readily disassembled to permit of replacement oi parts which have become worn.

The invention possesses other objects and features of advantage, some of which, together with the foregoing, will be specifically set forth in the detailed description of the invention hereunto N annexed. It is to be understood that the invention is not to be limited to the specific form thereof herein shown and described as various other embodiments thereof may be employed within the scope of the appended claim.

Referring to the drawing:

Figure 1 is a top plan View of the complete blast gun of my invention.

Figure 2 is a longitudinal vertical sectional view of the gun. The plane in which the view is taken is indicated by the line 2-2 of Figure 1.

Figure 3 is a transverse vertical sectional view of the gun. The plane in which the view is taken is indicated by the line 3-3 of Figure 2.

In detail, the blast gun comprises a preferably cylindrical metal barrel 4 having at one end` a diametrically enlarged boss i6 and at the opposite end a bulbous head 1. The barrel 4 is provided with an axial bore 8 which passes through a relief chamber 9, formed intermediate the ends of the barrel 4, and through an air chamber II which is formed by hollowing out the head 1. The purpose of the relief chamber 9 is to reduce the amount of metal that the drill, used in forming the bore 3, must pass through so as to lessen (Cl. Eil-1l) machining time and costs. A pair of axially concentric counterbores I2 and I3, formed in the boss 6, are in communication with one end of the bore 8. In the bore 8 is a tubular discharge duct I4 one end of which extends outwardly from the housing slightly beyond the end of the head 1, and the other end of which is provided with -a diametrically enlarged head I6 which is seated within the counterbore I3.

Means is provided for directing a blast of air under pressure into the discharge duct I4. Provided in the counterbore I2 are screw threads I1 which mesh with mating threads formed on a nipple I8, extending into the counterbore and comprising an extension of the shank |13 of adownwardly directed pistol-grip handle 2|. A flange 22, formed as an integral part of the shank I9, engages the end of the boss 6 and acts as a stop in limiting the amount of engagement of the nipple I8 in the counterbore I2. The shank20 I9 is provided with a central passage 23 which, at one end, is internally threaded to receive the threaded shank of a jet nozzle 24 which has a conical end 26 spaced from a complemental conical seat 21 formed in the end oi the discharge` 25 duct head I6. The spaced conical surfaces 23 and 21 provide an injector passage between the jet nozzle 24 and the discharge tube head I6. The jet nozzle 24 is provided with an orifice 23 which is axially concentric with the bore 29 of' the discharge duct. The other end of the passage 23 is directed downwardly within the handle 2|. The handle 2| is cored out so as to form a hollow chamber 3| separated from the passage 23 by a wall 32 and a hose coupling 33, threaded'- into the lower end of the handle 2| and adapted to be connected with a hose containing compressed air, is provided for admitting the compressed air into the handle chamber 3|. Formed on the handle 2| is a boss 34 which has a bore 36 therein piercing the wall 32 so as to provide for intercommunication between the chamber 3| and the passage 23.- The portion of the bore 3S in the boss 34 is threaded to receive the threaded body 31 of a control valve; the valve body being extended and formed with an end ange 38 positioned within and sealing the portion of the bore 3G which passes through the dividing wall 32. The valve body 31 is provided with an axial bore 39 `and with apertures 4| through which the bore 39 and the passage 23 are in communication. A valve stem 42, smaller in diameter than the bore 39, is positioned axially in the latter and has, at the end thereof within the chamber 3|, a disk valve 43 which covers and normally closes the end of the bore 39. The valve 43 may be mounted onthe end of the stem 42 in any suitable manner such as by the retaining washer and nut 44 shown. A head or push button 46 secured to the valve stem 42 has a hub 41 which enters and is slidably guided in a counterbore 48 formed in the valve body 31, a coil spring 49 being also contained in the counterbore 48 which engages the hub 41 and resiliently presses the valve disk 43 on its seat. It will be seen that when the push button 46 is pressed, the valve disk 43 will be moved to uncover the end of the bore 39 thereby allowing compressed air contained in the handle chamber 3I to iiow through the bore 39 and apertures 4I into the passage 23 through which it will iiow to be discharged through the jet orice 28 into the discharge duct I4. The construction of the control valve permits it to be removed as an integral unit from the handle 2| so that it may be inspected or the parts thereof replaced or repaired. Likewise, unscrewing the shank I9 from the boss 6 bares the jet nozzle 24 so that this part may be examined or replaced.

Means is provided for admitting material into the discharge duct I4 to be adm ixed with the stream of compressed air flowing therethrough. Formed on and extending radially from the boss 6 is a hub 5I internally bored and provided with screw threads 52 which engage mating threads formed exteriorly of a suction duct 53 which enters and is secured in the bore of the hub 5I. The upper end of the suction duct is provided with internal screw threads 54 which receive the correspondingly threaded stem 59 of a suction nozzle 51 which has a conical end surface 58 entering and seated in complementarily tapered and axially alined apertures 59 and BI formed, respectively, in the hub 6 and in the head I6 of the discharge duct I4. The upper end of the suction nozzle 51 terminates substantially flush with the periphery of the bore 29 of the discharge duct I4 and is provided with an aperture 62 through which the discharge duct bore 29 and the bore of the suction duct 53 are in communication. y

It will be seen that when a blast of compressed air is iiowing from the jet nozzle orice 28, and expanding in owing through the discharge duct I4, a reduced pressure will be created in the suction duct 53 and also in the injector air passage. Thus, when the suction duct 53 is connected to a container, in which a quantity of readily owable material is placed, the said material will be drawn, by the suction in the suction duct 53, through the latter and into the discharge duct I4 Where it will be immediately caught by and dispersed in the air stream flowing through the discharge duct I4 and will thereafter be blown from the end of the duct I4. Apertures 50 entering the counterbore I2 permit atmospheric air to be drawn through the injector passage into the discharge duct I4.

Means is provided for mixing additional quantities of air with the admixture of air and entrained material iiowing through the discharge duct I4 before the admixture is discharged into the atmosphere. Disposed concentrically with and extending beyond the open or discharge end of the discharge duct I4 is a tubular discharge nozzle 64 having screw threads 65 formed at one end thereof which engage in mating threads provided in a bore formed in the end of the bulbous head 1. The positioning of the discharge nozzle l 64 forms an annular duct 61 surrounding the end of the discharge duct I4 and entering the air chamber Ilvformed in the head 1. A plurality of circumferentially spaced openings 98 drilled through the side wall of the air chamber 'I permit communication of the latter with the atmosphere. It will be seen that when a blast of air and material entrained therein is flowing from the end of the discharge duct I4 it will create a suction in the annular duct 61 thus drawing atmospheric air, which has entered the chamber I I v through the openings 68, into the discharge nozzle 64 where it will become mixed with the blast and will augment the air contained in the mixture flowing from the discharge duct. This not only effects a more thorough dispersion of the air and material mixed therewith but also, when abrasive material such as sand is being carried by the air blast, forms an annular air cushion between the mixture, issuing from the discharge duct, and the inner periphery of the' nozzle 64 so that Wearing away of the latter, by the hard and sharpsand particles', is greatly retarded.

The blast gun above described is quite versatile in that, with very little alteration, it may be put to a wide variety of uses. For instance, since it will handle any flowable material besides sand, such as paint, insecticides, or inflammable oils or gases, it may, without alteration, be used, respectively, as a paint spray gun, a plant spray or sulfur duster, or as. a blow torch or oil burner. In addition to these uses it may be utilized as a vacuum lift to remove liquids or other fluent matter from inaccessible pockets or sumps.

Having thus described my invention in detail, What I claim as new and desire to secure by Letters Patent is:

A device 'of the class described comprising a substantially cylindrical barrel having therein an axial bore and a concentric auxiliary fluid chamber,said barrel having adjacent an end of said axial bore a frusto-conical opening axially perpendicular to and intersecting the axis of said barrel bore; a tubular member removably positioned in said barrel bore and provided with a bore forming a fluid discharge duct, said tubular member having adjacent one end thereof, and in axial alinement with the frusto-conical opening of the barrel, a complementary frusto-conical opening, a handle member removably secured in said barrel and having therein a passage to be connected at one end with a source of fluid under pressure, a jet nozzle connected with said handle member and having therein an orifice in communication with said handle passage and through which said fluid under pressure may flow into an end of said fluid discharge duct, a valve in said handle for controlling the flow-of said fluid under pressure through the handle passage and the said orifice thereof, a suction duct, through which fluent material may ow, connected with said barrel, a suction nozzle connected with said suction duct and having a conical end portion entering and seated in' the axially alined frustoconical openings cf said barrel and said tubular member, said suction nozzle having therein an -aperture opening into said discharge duct, in

communication with said suction duct, and spaced longitudinally of said tubular member from the jet nozzle orifice, a tubular discharge nozzle mounted on an end of said barrel in concentric relation with said tubular member so as to provide therebetween an annular passage, and said annular passage beingr in communication with said auxiliary iiuid chamber.

LUIGI LANZA. 

